


Playing Doctor

by crocodilepatronus



Category: DCU (Comics), Smallville, Superman - All Media Types
Genre: Alien Biology, Alien Sex, M/M, Medical Kink, Non-Human Genitalia, Pheromones, Sexual Roleplay, Tentacle Sex, Tentacles, Xeno, Xenophilia
Language: English
Status: Completed
Published: 2019-07-07
Updated: 2019-07-07
Packaged: 2020-06-23 19:13:40
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,636
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19707700
Author URL: https://archiveofourown.org/users/crocodilepatronus/pseuds/crocodilepatronus
Summary: Clark may look passably human with all his clothes on, but Lex knows he has secrets underneath... (essentially an excuse to write about some of my favorite Kryptonian biology headcanons and tentacle Clark)





	Playing Doctor

“You know.” Clark sighed. “I’m not thrilled about this.”

There was an audible snap as Lex secured a pair of latex doctor’s gloves over his hands. He looked over his shoulder at Clark, frowning. “You made me roll in hay when it was YOUR turn to choose your fantasy roleplay. This is the LEAST you can do to repay me.”

Clark squirmed against the restraints holding him to the table. It was cold metal on his bare ass and thighs and he couldn’t find a position where he was comfortable. He supposed that was the point.

It was of course, after so many years together, no surprise to Clark that Lex was kinky. But he’d been trying to stubbornly draw the line at Lex’s ‘alien autopsy’ fantasy for a while, no matter how many times it was brought up half jokingly. The real fear was that Clark usually found whenever Lex tried to talk him into these types of roleplays that HE ended up being the one who enjoyed them more than intended. Well- except for the candle wax dripping. That had just been boring.

“This sort of sucks on my end.” he complained. He would’ve crossed his arms over his chest petulantly if they weren’t strapped down.

However, Lex always looked nice in a white lab coat. Clark could appreciate that part.

Lex was having fun looking over his operating instruments with an evil glint in his eye, picking up different pliers and scalpels and examining them before putting them back down again. His set of stainless steel toys glimmered menacingly in the nauseatingly bright fluorescent light

“You know those won’t work on me if they’re regular metal.” Clark said dryly.

“Let me have my fun.” Lex replied coolly.

“Can you speed up your fun? My butt is going numb on this table.”

Lex practically sashayed over, a tape recorder in one hand and forceps in another. He took a deep inhale, wicked smile on his face, and said dreamily “I’m really going to enjoy this.”

Clark rolled his eyes.

Lex hit the red record button on the hand held tape recorder and spoke into it: “Subject is an adult Kryptonian male.”

Clark jumped at the first feeling of latex on his skin. He’d rarely been examined by doctors all his life, for obvious reasons. He wasn’t used to this type of attention. In fact, Lex was one of the first people Clark had ever let really examine his body naked. Lex wasn’t his first- previous much trusted lovers had been witness to Clark’s…. strangeness. But none were scientists.

He’d actually been terrified the first time he’d undressed in front of Lex. He could still remember the sound of his own heart beat and the sound of Lex’s breath catching in his throat. And then the smile that had spread across the other man’s face. And the relief that had flooded through him.

Now Lex knew Clark’s body intimately but for the sake of the play they were engaged in he was touching him with a reverence as if it was their first time. Rubber gloved fingers traced every detail of his skin, starting with hands.

“While the exoskeleton resembles a human’s, the epidermis is as strong as titanium.” Lex continued to speak into the recorder.

“Man of Steel” may have been a misnomer. It wasn’t that Clark’s flesh was HARD per se, it was impermeable but had the same soft, smooth, texture of human flesh. Yet under threat of harm it seemed to go stiff and resistant. Lex could squeeze and pinch at the skin with no problem but he knew from experience that if he were to attempt to breach it with a scalpel, it would harden like a shell until the scalpel broke or was removed.

In fact, because Clark was impervious to harm he was actually incredibly smooth. Lex had never known a farmboy with hands so soft and free of callouses. Even the soles of his feet and the pads of his toes were silken. If someone didn’t know any better, they could think Clark had led some sort of pampered lifestyle. In fact, even Lex who had never done much manual labor and went to a spa once a week had more texture to his skin than Clark did.

The only place where there was roughness was on his knuckles. Lex figured that was because the only time anything ever marred his flesh was in a serious fight, and it had left nearly imperceptible scar tissue.

He ran his own fingertips over Clark’s hands, admiring the difference in size. Clark’s hands were very large, with a wide palm. Lex had long, spindly, slender fingers and narrow wrists.

Clark in general was much larger than Lex. For a while it had annoyed Lex, that Superman stood a few inches above him. Even when they’d been younger, Clark had been significantly taller and much more muscular. Now, Lex rather liked the difference in size- it afforded more satisfaction when he had Clark underneath him, nuzzling his face against Lex’s hand, arching his back and begging.

Clark had the body of a Greek hero- every muscle perfectly sculpted like he was made out of marble. And Lex loved seeing it fully nude under bright light, getting to soak in the image. Clark was shy and liked the lights dim when they had sex but if he had his way, Lex would photograph and examine him from every angle, splay him, bend him, until no inch of him was a secret any longer.

Lex smirked as he circled his gloved thumb around Clark’s nipple. “Two mammary papilla, surprisingly sensitive to the touch implying it may be a nerve center.” He pinched it hard enough that Clark made a stifled noise.

Satisfied, he smoothed his hand down Clark’s abdomen, and down to his bare crotch.

This was the area Clark was most self conscious of. Because it was the place where his body was most different than a human’s.

There was an… appendage…. And it was roughly the size and shape of an average human penis... However, there was no foreskin and where the blood collected, instead of being red or pink, it was tinged in a bluish green like an artery. And most strikingly, the shaft was surrounded by 3 longer, slender, appendages that resembled tentacles. They were slick and sheathed in a much thinner, more translucent, skin than the rest of his body and a darker color of blue. They only unfurled from his body and took on color when he was aroused.

“The kryptonian’s genitalia includes a phallus. There is no prepuce or scrotum.”

He trailed his fingers over them, taking one of the tentacles in his hand and gently pulling it away from his body until it was fully extended, though still limp.

Then Lex took out a cloth measuring tape from out of his pocket and Clark balked.

“H-hey now. Do we really need an exact size?”

“Aren’t you curious?” Lex asked innocently.

“No!” Clark snapped, feeling heat spread from his cheeks to the tip of his ears. “Why does it matter?!”

Lex chuckled. “Don’t tell me you’ve become prone to the all too human insecurity about your size.”

This gave Clark pause. In fact he WAS a little curious to see who was bigger- himself or Lex…. He’d eyeball’d a comparison long ago but of course it had always been difficult to Clark for judge, his parts were different enough that he’d never really known where he stood in reference to other boys in the locker room or such.

“Well…. fine, then. Go ahead. But don’t cry when I’m bigger than you.” Clark sniffed haughtily.

Lex shrugged one shoulder and extended the tentacle again, holding the measuring tape to it. “Each of the softer appendages around the main phallus is roughly 7 inches with a when the subject is not in a state of arousal and without stretching. They do however have a great deal of elasticity which won’t be tested for the sake of the subject’s comfort.” Lex spoke into the recorder, carefully curling the tentacle back to lie around Clark’s abdomen. Clark squirmed a little bit but tried to take it stoically. The tentacles were particularly sensitive when he was relaxed.

Lex took his shaft in his hand with a clinical boldness, wrapping the tape measurer first around the girth of it, then holding it in his palm to stretch the tape across the length. The organ twitched with interest at the warm touch.

“4 inch girth and a 7 and a half inch length while flaccid. Congratulations, Clark, you fall within the American average.” Lex said with a pointedly smug look.

“Average?!” Clark nearly shot upright if the leather bands hadn’t been holding him back just enough to remind him they were in the middle of play. “There’s nothing average about- about- my--- ** _that_**!”

“Well in terms of size you’re statistically normal.” Lex dropped the tape measure back in his pocket and pulled up a stool on wheels to sit between Clark’s spread thighs. “But, yes, the average American penis doesn’t have the extra… _trimmings_ , that yours does.” he quipped, glancing at the tentacles with a raised eyebrow.

“I think you love my trimmings.” Clark grinned.

Lex pulled his gloves on tighter with a snap. “I’m going to prep to test the subject’s internal elasticity.” he said into the recorder.

Lex forced Clark’s thighs up and open and placed his feet into the stirrups on either side of the bed, strapping them down in place by the ankles. Clark swallowed anxiously. The air felt cold on him where he was open and vulnerable. Even Lex’s hand sliding up his thigh didn’t comfort him much.

When the first finger squeezed into him he made a small noise of surprise. He was so used to having Lex’s fingers in him but never with rubber gloves like this. It felt different and sent a chill of excitement down his spine. Clark liked to be at Lex’s mercy. They toyed with the idea frequently in their bedroom play. Clark had rarely in his life met people who had physical advantage over him so to give over control, let himself be fully vulnerable with his partner, felt like the highest form of intimacy.

And of course, Lex loved to **_have_** Clark like this. Through handcuffs, straps, ropes, any type of illusion of bondage. His very own God pinned like a butterfly in a frame, just for him. Those marble cut muscles struggling, the pleading want in his sky blue eyes and parted lips, every inch of his beauty laid out for Lex to take. And that he would always be magnanimous to show Clark the mercy to give him everything he wanted…

“There appears to be an erogenous zone about 3 inches deep-”

Clark yelped as Lex’s fingers cruelly dug into the spot, wringing out painful pleasure.

“- and quite a sensitive one at that.” Lex said with satisfaction.

He wheeled his seat back and grabbed something off his little side table of shiny instruments before coming back. Clark thought that if Lex was too mean to him he would be cruel enough to point out that the fluorescent hospital lights glinted off the top of his bald head whenever he leaned over. He’d barely suppressed a laugh at the thought before he felt something very cold and metallic nudging at his anus.

“COLD!” Clark shouted. “WHATEVER THAT IS, ITS COLD!”

Lex made a ‘tsk’ noise and held up the object within Clark’s line of sight. It was a metal speculum. Clark felt the blush covering his cheeks.

“I don’t think that’s meant for-”

“It’s fine.” Lex assured him, raising an eyebrow and grinning salaciously. “I’m a scientist, Clark. I wouldn’t do anything to hurt you.”

Clark didn’t bother bringing up that he’d spent many years doing nothing BUT trying to do just that but warily relaxed his thigh muscles as Lex squirted a generous amount of lube on his fingers and began massaging then slowly scissoring open his entrance once more. It felt good and in moments Clark’s head was thrown back, little whimpers of pleasure escaping his lips.

Lex smirked to himself as he watched his three fingers disappear into Clark’s body as he thrust in and out rhythmically, making sure to tease his sweet spot just enough to keep him on the edge.

“That’s it…” Lex praised soothingly. “You’re sucking me in like you want something bigger. Don’t you?”

Clark’s breathing came out ragged. He lifted his head up slightly from the table and looked at Lex with eyes glassy with lust as he nodded.

He smeared more lubricant on the speculum and slowly began pushing it in as his fingers withdrew, making sure he wasn’t empty for even a second. The instrument pushed into him nice and slowly, Lex stroking Clark’s thighs, hushing him when he began to make little gasps and squeaks until it was fully inserted inside him to the handle.

“How does it feel?” Lex asked.

Lex kissed Clark’s inner thigh as he slowly pressed on the handle of the speculum, opening it a tiny amount at a time. He heard the air get knocked from Clark’s lungs in a gasp.

“A-ah…” Clark stammered, breathing hard. “Full… feels….” he swallowed roughly.

“Should I keep going?” Lex peered up from between Clark’s thighs to look at his face. His hair was sweaty, forming dark ringlets across his forehead, his eyes closed and his lashes looked so dark fluttering against his cheek. “If it’s too uncomfortable we can stop for the night.”

“No! No…” Clark’s eyes flew open, wet and pleading as they looked down at Lex. He swallowed thickly, taking a deep breath. “It feels…. good. I’ve never felt anything like it, that’s all.”

Lex smiled, giving another chaste kiss to the side of Clark’s thigh before he slowly began opening the prongs of the speculum once more, half inch by half inch until Clark’s entrance was gaping, the rim completely taught. Clark was panting like he’d just run, his chest shaking as he tried not to bust out of the restraints.

“You’re being very brave.” Lex coo-ed at him. “Does it hurt at all?”

Lex had seen Superman thrown through buildings and pelted by bullets with no reaction but such simple things could undo him when he was naked and vulnerable. Clark didn’t have much experience with pain and it terrified him and excited him. Made him feel more human.

“I just … don’t think I’ve ever stretched this much.” Clark moaned, turning his head to the side on the examination table. “F-feels like…” he blushed. “Feels like there’s two of you inside of me… Except, I can feel the air.…” he trailed off, too embarrassed to put the rest into words.

“You look beautiful, you know.” Lex said reverently, running his fingertips around the rim which was red and swollen under the attention it was receiving. “The vulnerable parts of your body are always beautiful to me… The parts only I get to see…”

He used his fingers to probe inside of him, until he found Clark’s sensitive spot again and began rubbing his index finger against it expertly making Clark arch his back against the table and grit his teeth.

“I can practically fit my whole fist inside you like this.” Lex purred, adding another finger and digging into the spot, rubbing over it rhythmically. He could feel Clark quivering, making little needy sounds a the back of his throat. And when he looked over he saw that the tentacles around Clark’s genitals were beginning to unfurl and the dark colored cock was jutting out.

Lex smiled smugly at Clark’s erection. “Now, would you look at that.” he said softly.

“Oh, shut up.” Clark said through gritted teeth.

Lex ignored him and spoke into the recorder, smile now in place on his face. “When aroused, the kryptonian’s genitals unfurl, and fill with blood.”

It looked beautiful. One of the most beautiful things Lex had ever seen and a sight he never tired of. Clark’s genitals were just like a flower, the phallus in the center the stamin and the three tentacles around it the petals.

The tapered head of each tentacle was very thin, smaller even than a pencil tip, and very flexible. The tentacle the way it was, mostly at rest, was as thick as three fingers at the base but it could stretch, extremely elastic. Once aroused, it moved almost as if it was filled with jelly, changing its form easily.

Lex knew another secret of Clark’s. Possibly one more dangerous than his real identity, or that kryptonite could be used against him. It was a strange quirk of Kryptonian biology. His body became more supple and vulnerable when he became sexually aroused. It wasn’t as effective as kryptonite in stripping his powers, but in the throes of passion Lex had sucked bruises onto his skin before, been able to take Clark’s lower lip between his teeth and bite down until he tasted blood.

How ironic, that Lex had dedicated years and years to finding Superman’s weaknesses and all he’d had to do was get him in bed.

He’d never told anyone. It would be a disaster for any of Clark’s enemies to find out. Soon there would have been no shortage of evil seductresses and succubi knocking on Metropolis’s door trying to lure Clark into a place of vulnerability.

And besides, Lex wanted to be the only one who could have Clark this way.

Lex ran the tip of his finger across one of the tentacles and it immediately responded by wrapping itself three times around Lex’s wrist and squeezing down. “Eager, are we?” he asked dryly.

He let his fingers stroke the tentacle wrapped around his wrist, beginning to slide his palm up and down it. In response, it began to go slick, dewey droplets coating it of- “Subject is releasing a pheromone.” he pulled his hand away, the tentacle reluctantly releasing him, and sucked his own fingers, savoring the familiar taste. It was a different taste than a human’s. Almost herbal- sharp and slightly numbing against his tongue. “This pheromone doubles as a lubricant and numbing agent.” he informed the recorder, circling around the table and admiring from every angle.

“I’m going to take this out.” Lex warned Clark, carefully closing the speculum down in size and sliding it out. He replaced it with his fingers, thrusting a few times to make Clark arch off the table. Then he leaned forward, laving his tongue along the shaft of his genitals.

Clark groaned as Lex took him into his mouth, sucking him down to the base with practiced precision.

Clark’s tentacles responded to the attention on him. One roped around Lex’s neck, twice, squeezing hard enough for it to hurt. The other was rubbing and caressing the back of his scalp, licking at the curve of his head.

As he struggled for air and gagged around the appendage down his throat, his eyes began to water, blurring the sight of Clark in front of him. He blinked and felt wetness on his lashes and a drop trickle out of the corner of his eye. He whimpered feebly, trying to pull his head back. Clark allowed him a little give and Lex inhaled deeply through his nose, before the tentacle brutally tugged him forward again, going even deeper than before until he could feel the tickle of its tip at the base of his throat. Drool dripped down his jaw, seeping out between his aching lips.

A few more thrusts down his willing throat and Lex finally pulled away, unroping the tentacles that had furled around him.

Lex stood up, licked his lips as he unbuckled his belt and dropped it to the floor.

Clark panted as he watched Lex undress, his eyes glazed over and his tentacles thrashing about in frustration, curling and rubbing against the hair on his own stomach and thighs for some type of friction.

“Please, Lex…” Clark gasped.

When Lex was fully nude he climbed onto the examination table, on his knees at first by Clark’s feet as he took a healthy dollop of the lube from the side tray and began slicking himself with it, using two fingers.

Clark whined, rolling his hips up against the air. “Let me do it. Please, let me, Lex. You know I love to.”

“Shh, I will.” Lex said, patting his thigh soothingly and scooching forward on the examination table until his hips were poised above Clark’s. “Okay. Now you can start.”

Clark sighed in relief and one of his tentacles curled upward then slowly breached Lex, first at its very most narrow tip, teasing inside slowly and gently. Lex was biting his lower lip in anticipation, already lowering his hips onto the appendage.

As he did so, one of Clark’s other tentacles wrapped around Lex’s cock, beginning to squeeze and tickle at it teasingly, smearing the pheromone liquid across the shaft.

The effect was almost immediate, Lex’s cock began to drip and his face flushed. Clark could control it to a certain extent, how much he excreted. And the effect was never mind altering, just a bit of purely physical encouragement. 

Clark’s tentacle was pumping into Lex at a fast pace now, plunging its full width into him. Lex’s body shivered everytime it entered him fully. It had taken some practice at control but now Clark could tickle Lex inside at just the right places, coiling and rubbing slickly until Lex’s hole was dilated and wet with the pheromone, until every part inside of him was a pleasure center.

Clark loved to see Lex undone with lust, riding him, head thrown back exposing the elegant curve of his neck. He wished he could use his hands to touch him, could use his mouth to leave marks all across his collarbone and taste his sweat. But he supposed that was part of the purpose of the exercise- that he couldn’t. Lex got to do whatever he wanted to him, and Clark had to go at his pace.

“I’m ready for you…” Lex nodded weakly. He looked in a trance with pleasure, his jaw slack and his lips swollen and red. Clark slowly removed the tentacle from him. Lex winced at the new emptiness but quickly moved forward a few inches, spreading himself with his hands and lowering himself onto Clark’s phallus. It was considerably thicker than the tentacles, and was at full mast now, pulsing and dark blue at the tip.

A tentacle was wound around each of Lex’s thighs, holding them in place and guiding the movement of his hips. The third was wrapped around his cock, enveloping it, twitching and tightening its grip with each stroke up and down.

He was fucking Lex raw. His whole body seemed to bounce on each jerk of Clark’s hips as the blunt tip of his cock buried itself in him. There was sweat dripping down his chest, his skin glistening under the fluorescent lights.

Clark began to slow his movements. The only part of his body in his control currently was his hips and his genitals. They were the only part of him not strapped down to the table. So he planned on using as much of that control as he could get. He started rolling his hips up languidly into Lex, so every in and out motion dragged against him-making him savor it.

Lex gasped as the tentacles around his thighs released and slowly one began to tease around the edge of his hole, where Clark’s cock was still buried, and began to slither inside.

“F-f….” Lex stammered, scraping his fingernails down Clark’s chest and practically hyperventilating as it pushed its way inside, stretching him so wide he felt he’d tear.

“You like that?” Clark panted, gritting his teeth. “You’re so fucking tight… so full with me… I love you like this… “

The tenacle was not as thick as Clark’s shaft but it could wiggle around inside him, and Clark knew Lex’s body. The tip of it soon found Lex’s prostate and began stroking and curling against it, rubbing along it with the thin tip and massaging it like a finger would, but more slicked, more precise.

When the other tentacle began to nudge its way inside on the other side of his hole, Lex began groaning loudly, his eyes rolling back as he squirmed and tensed at the intrusion. He had one shaft pumping inside him at a steady rhythm and two tentacles on either side of it, squirming and fighting for space, massaging and teasing him on the inside.

He was so full he was burning, could think of nothing else. His brain felt flat lined and that was a rarity for Lex Luthor. Any thoughts he had were scrambled nonsense- need, fuck, Clark, good, please, please, fuck, full…. The garbled moans and helpless whimpering coming from his mouth were equally incoherent.

“Lex… LEX….. God, so tight…. Lex… need you…. undo the restraints” Clark managed to shout between nearly frantic gasps and bitten back groans. Lex barely heard him. His head was lolling back, his mouth open but making nothing but choked, desperate, sounds. But he managed to reach over to the side table, grabbing blindly for the controller and hit the switch that unlocked the restraints on Clark’s wrists and ankles. In a flash Clark was sitting up, wrapping his arms around Lex and curling his upper body around him, kissing and biting hard at his neck and shoulders.

“I wanted you so bad” Clark’s voice was strained, ragged as he pressed wet kisses against Lex’s jaw “Couldn’t take it… Wanted to touch you…” His mouth found Lex’s and took it ruthlessly, sucking at his tongue and sinking his teeth into his lips.

As if in reward for unlocking his restraints, the tentacle Clark had wrapped around Lex’s cock began pumping faster, squeezing tighter. And the tentacles and cock in him started to thrust in shorter, quicker, bursts. Each shallow movement stretching and pulling at Lex’s rim. Then abruptly he pulled out almost all the way, leaving Lex’s hole gasping and twitching before being filled again in one long thrust that knocked the air out of his lungs. He reached his climax breathless and with his eyes rolled back, choking on Clark’s name.

He went limp in his lover’s arms, mouth hanging open and eyes fluttering closed. He was so weak he would’ve collapsed if Clark hadn’t been holding him up. But Clark was not done with him, still with three appendages deep inside of him, painfully holding him taut and open. Even the tentacle that wasn’t penetrating him was squeezing and rubbing against his newly oversensitive and spent cock.

Clark keened as he came, the sound muffled by the flesh of Lex’s neck that filled his mouth as he bit down lightly, but still hard enough that it would leave a mark Lex would complain about the next morning.

His body was shaking like a leaf as he held Lex loosely, still panting as if he needed air to live. The tentacles and phallus were going limp and he slowly withdrew them from Lex, careful not to harm him when he did. The organ drew back in on itself, tucking itself away into a neat bundle hanging between Clark’s thighs once more.

They lay next to each other, out of breath and too dazed and overfucked to speak for a while.

“So…” Clark finally said after a time. “In your scientific opinion, what’s your diagnosis of this alien…?”

Lex snickered and leaned up to kiss him. “You require much further examination. I think you should come back for some more tests. Maybe tomorrow night.”


End file.
